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April 2000


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Lucia Clontz <[log in to unmask]>
Reply To:
The Pharmaceutical Microbiology Mail List <[log in to unmask]>
Mon, 17 Apr 2000 13:02:05 -0400
text/plain (66 lines)
Hi Martin,

yes, you can use MF to test disinfectants for bioburden and to qualify
disinfectants. You must ensure the compatibility between the membrane
filters and the product.

For the validation of a bioburden method, you can use the organisms listed
in the USP/EP using a low-level inoculum challenge (less than 100 CFU)

For qualification of disinfectant efficacy, I recommend the use of
organisms that represent typical contaminants in a pharmaceutical
manufacturing environment. Most of these organisms are included in the
USP/EP tests and in the AOAC. For example:  Staph. aureus, Staph
epidermidis, Bacillus subtilus, Candida albicans, A. niger, Ps. aeruginosa,
E. coli, and Salmonella spp. The use of environmental isolates is always a
plus and has become a regulatory expectation.  For these tests, most
companies use a high challenge in the range of at least 10E3 CFU.  You must
perform neutralization studies during your qualification studies in order
to  ensure the validity of the data (which is basically the validation of a
bioburden recovery method).

For qualification of disinfectant efficacy, most people are also conducting
surface testing, i.e., qualifying the actual use of the disinfectant as
applied to the different types of surfaces and with different types of
application and contact times. In this case, you also need to consider
performing some type of recovery study to qualify your environmental
monitoring methodology (contact plate or swab).

I think I covered more than you asked for, but I hope it helps.

Lucia Clontz
Serentec, Inc.

At 11:48 AM 4/16/00 +0000, you wrote:
>1) Is a membrane filtration method for validation of bioburden in
>disinfectant solutions covered by the 'membrane filtration methods' in
>the European and United States Pharmacopoeia?
>2) Which environmental isolates would we challenge the method with if
>our production environment surface contact plates very rarely show
>growth? Is it acceptable to use only the organisms listed as for bulk
>bioburden methods in the EP/USP?
>Martin Sarosi
>on behalf of Pharmig
>The PMFList ( is operated from
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